Facultative secondary symbiont drives the physiological and metabolic alterations of insect host

Lepidoptera comprise the second most diverse insect order in worldwide, including some of the most devastating agricultural pests and important economic insects. Silkworm is an ideal model for studying the symbiosis between bacteria and insects. Bacterial secondary symbionts in the gut are widespread in insects. Symbionts often enhance host ability to acquire nutrients from the environment or provide the pathways for synthesis of needed organic compounds or for catabolism of molecules available in the environment. B. subtilis is one of the main components of symbiotic bacteria in the digestive tract of silkworm. Previous studies have indicated that B. subtilis can promote the growth and development and maintain health of silkworm. However, to date, the ecological role of these Bacillus relatives to the Lepidoptera remains obscure. Therefore, in this study, we employed the B. subtilis isolated from silkworm intestine to explore the mode of action of Bacillus on Lepidoptera.

鳞翅目（Lepidoptera）是全球物种多样性第二高的昆虫目，涵盖诸多毁灭性农业害虫与重要经济昆虫。家蚕是研究细菌与昆虫共生关系的理想模式生物。昆虫肠道内的细菌次生共生菌分布广泛。共生菌通常可增强宿主从环境中获取营养的能力，或是为宿主合成必需有机化合物提供代谢通路，亦或是参与分解环境中可利用的分子。枯草芽孢杆菌（B. subtilis）是家蚕消化道共生菌群的主要组成成分之一。既往研究表明，枯草芽孢杆菌能够促进家蚕的生长发育并维持其健康状态。然而截至目前，这类芽孢杆菌对鳞翅目昆虫的生态功能仍不甚明确。因此，本研究采用从家蚕肠道分离得到的枯草芽孢杆菌，旨在探究芽孢杆菌对鳞翅目昆虫的作用机制。